Opera (15-26) gets very slow as Sessions.db gets large

@lando242 Windows 8.1 Enterprise with 8gb of Ram.
I deleted the session.db file and restore my tabs this morning and already the file is back up to 79mb. I'm not sure at what size it starts to get noticeable but its somewhere around 130mb or so, most noticeable when scrolling in web pages.

Instead of just deleting the session file have you also tried changing the 'On startup' option to something other than Continue where I left off? I use Session Buddy for all of my session needs and just have its management page set as one of the pages it opens when I start the browser. That makes it super easy to pick up where I left off even if the browser crashed. Which, to be fair, hasn't happened at all since they fixed that Ctrl+F bug in the Dev channel awhile back.

I have the same problem too. I am someone that could be called as "heavy user". Normally I don't close Opera in days and I use to have an average of 15+ tabs opened at the same time.

I'm noticyng laggy from some time, maybe months. When I first realise it, I restarted opera (and all the opened tabs) but was the same. I tried closing all the tabs but surpresively still was laggy. It was specially noticiable in videos, that every 10 seconds aproximatedly has a "micro stop". That happens with all the videos, all the websites in flash or html5 and for example in Firefox with the same opened tabs it doesn't happens.

I just did the same that "guido11x" and renamed the Opera Next folder in %Apdata% and it worked flawlessly so probably the problem is inside, i don't know.

My specs are: Intel i5-2500k, 16GB Ram, SSD and AMD 6850HD in Windows 8.1 up to date and the latest Opera Next

The session db seems to be unrelated to saved browsing data and history, since cleaning up Opera's browsing data (Ctrl+Shift+Del) doesn't help.

Even after deleting site data - cookies and so on - the problem still persists.

There seems to be no difference between pinned and unpinned open tabs

Disabling all extensions doesn't help, so it's not their fault that Opera lags.

Possible solutions:

Deleting session.db and session.dbak. I tried leaving the journal file and haven't seen and unwanted effect, so just let it be...

As mentioned, disabling extensions doesn't help when Opera is already lagging and session is already big, BUT disabling certain extensions, such as Autopagerize (all sites concerned) seems to slow down the expansion of this session file.

This leads me to believe:

Maybe there's a bug in Opera that doesn't simplify/decrease this session file, leading to expand in size and as a result, slows down Opera.

Maybe some extensions help to worsen this bug, adding more stress to the file.

It seems that as long as session.db maintains its size under some MB (preferablly under 1MB), Opera runs fine. So keep an eye on your file.

Please share your experience on this issue and also maybe solution too.

It looks like this issue isn't just a problem in Opera for Windows. It's the same for me with Opera 29 for Mac.
Things generally get worse and worse until you start again with new session files. It's making Opera almost unusable at the moment.

All browsers fail at some point, be it IE, Firefox, Chrome, Safari and the one I use now, Opera.
It builds and builds and builds. After navigating only 3 or 4 websites it starts to slow.
Gets slower and slower the more you use it.
Forget having more than 4 tabs open. It doesn't like that at all.
Go to Facebook and don't expect any of the other tabs to open whilst you go and grow a tea plantation and collect the leaves and make a cup of tea.
Nothing cures it.
All I can do is logout and login to Opera again.
Then the same happens.
I use Vista and download speed is 7 meg. 1gig mem, 160 gig HD.
Obviously something somewhere is grabbing the CPU for god knows what.
I refuse to go round deleting stuff anywhere just because the Opera code is at fault.
Opera, you fix it or be doomed to the discard pile of failed browsers.

1 gig of memory on Vista? OUCH! Thats like 1/4th of what you need for that OS. RAM is cheap now, bump that guy up to 4 gigs and your life will be so much better. With only a gig of RAM your system will be making heavy use of the swap file on your hard drive and that is a lot slower than RAM. The more programs/windows/tabs you have open the more you use that swap file and the slower your system will get.

As for having a bunch of tabs open I currently am rocking 5 windows (4 normal, 1 private) with a total of 29 tabs across them. I regularly jump to 6-7 windows and hundreds of tabs when doing something. My system was last rebooted on the 29th of August and Opera has been running continuously since that time. I regularly run it much longer than that without issues (had to reboot for Windows Updates). I'm using Windows 8.1 but I did the same stuff with Opera on Windows 7.

This can be some misconfigured antivirus software interfering. I have seen such behavior with older Opera, when antivirus intercepted all temporary files traffic and made it very slow; possible that similar problems can arise with newer Operas too.

Vista HDD background indexing is not that optimal either; I had it disabled on Vista. With 1GB RAM Vista struggles with file caching; background disk access (both indexing and antivirus) slows it down substantially.

Another, pure browser problem can be some extension - try private window, extensions do not run there.

Then enable or disable graphic card display acceleration (I really can't say, where exactly in Opera is option for that, but it is possible) - sometimes (old) video drivers are not 100% compatible.

1 gig of memory on Vista? OUCH! Thats like 1/4th of what you need for that OS. RAM is cheap now, bump that guy up to 4 gigs and your life will be so much better. With only a gig of RAM your system will be making heavy use of the swap file on your hard drive and that is a lot slower than RAM. The more programs/windows/tabs you have open the more you use that swap file and the slower your system will get.
As for having a bunch of tabs open I currently am rocking 5 windows (4 normal, 1 private) with a total of 29 tabs across them. I regularly jump to 6-7 windows and hundreds of tabs when doing something. My system was last rebooted on the 29th of August and Opera has been running continuously since that time. I regularly run it much longer than that without issues (had to reboot for Windows Updates). I'm using Windows 8.1 but I did the same stuff with Opera on Windows 7.

Thanks for your excellent reply. I tend to hang on to any PC that works for way too long. I wondered if it was a lack of memory, in fact, couldn't imagine what else it could be apart from inherent coding limitations of the Opera browser. So yes, a memory upgrade is simple and cheap enough. Thanks

This can be some misconfigured antivirus software interfering. I have seen such behavior with older Opera, when antivirus intercepted all temporary files traffic and made it very slow; possible that similar problems can arise with newer Operas too.
Vista HDD background indexing is not that optimal either; I had it disabled on Vista. With 1GB RAM Vista struggles with file caching; background disk access (both indexing and antivirus) slows it down substantially.
Another, pure browser problem can be some extension - try private window, extensions do not run there.
Then enable or disable graphic card display acceleration (I really can't say, where exactly in Opera is option for that, but it is possible) - sometimes (old) video drivers are not 100% compatible.

I will give that a go, as well. I was hoping chucking the almost full half of my partioned HD into the almost empty half might help, too.